Boccolini Alessandro, Marques-Hueso Jose, Richards Bryce S
Opt Lett. 2014 May 15;39(10):2904-7. doi: 10.1364/OL.39.002904.
This Letter details a theoretical investigation of self-absorption within an upconverter (UC) material, consisting of trivalent erbium (Er3+)-doped hexagonal sodium yttrium fluoride (β-NaYF4) and its implications on two experimental situations: the case of a quantum yield measurement, and on the effective performance in a UC-enhanced photovoltaic (PV) device. The study demonstrates that an optimization of the thickness is essential in order to reduce the effect of self-absorption and maximize the possible additional photocurrent that could be harvested. It also has been found that the external photoluminescence quantum yield (ePLQY) measured through an integrating sphere may result in an underestimation with respect to the performance that the UC material could achieve in a UC-PV device. Finally, it has been found the optimal thickness and the molar concentration of Er3+ ions are inversely proportional, suggesting that an optimal number (1.3-2.9·10(17)) of Er3+ ions should be contained within the UC layer.
本信函详细介绍了对上转换（UC）材料中自吸收的理论研究，该材料由掺杂三价铒（Er3+）的六方氟化钠钇（β-NaYF4）组成，及其对两种实验情况的影响：量子产率测量情况，以及在UC增强型光伏（PV）器件中的有效性能。研究表明，优化厚度对于降低自吸收效应和最大化可收集的额外光电流至关重要。还发现，通过积分球测量的外部光致发光量子产率（ePLQY）可能会低估UC材料在UC-PV器件中所能达到的性能。最后，发现最佳厚度与Er3+离子的摩尔浓度成反比，这表明UC层中应包含最佳数量（1.3 - 2.9·10(17)）的Er3+离子。
